Much attention has been focused on the use of illicit drugs by people from all facets of American life. One of the most popular drugs which has been abused for over two decades by our society is marijuana. The drug is being used by people from all segments of our society including blue and white-collar workers, military personnel, professional athletes, and by high school students. Because of this problem many companies, including the U.S. Military, are now beginning to demand that employees suspected of drug use undergo drug testing. A variety of methods are available for specific and sensitive determination of marijuana and its major metabolites in biological fluids. Most of the available assays (i.e., HPLC, GC-MS), require expensive equipment, trained personnel, and are slow in determining if cannabinoids have been consumed. We propose to develop an enzyme immunoassay (EIA) which will be useful for the detection of low concentrations of the major cannabinoids in blood. Blood obtained by a fingerprick can be annalyzed directly by our assay thus eliminating possible sample contamination. This qualitative assay would serve as an excellent screen for possible cannabinoid abuse, but all positive samples would require verification by more sensitive and quantitative assays (i.e., GC-MS). The assay is simple, fast (less than 10 minutes), noninstrumental and thus easily portable for use in the work place.